Transmission Media In Computer Networks
Transmission Media In Computer Networks Transmission media is the part of the physical layer that provides a path through which data is transmitted from one place to another in computer networks. It is also known as a transmission channel, Communication media, or communication channel. Important The amount of data that can be transferred through a […]
Physical Layer
Physical Layer The physical layer is the last layer from the sender and the first layer from the receiving side in the OSI model. Note: Generally we assume the numbering of OSI layers according to Receiver Side. The Physical Layer transmits raw bits in the form of signals, which can be analog or digital, through […]
TCP/IP Model
TCP/IP Model The TCP/IP model was developed by the Department of Defense (DoD) in the 1970s and adopted as the protocol standard for ARPANET in 1983. TCP/IP is a practical model that is used to communicate with different devices over the internet. This model does not contain proper documentation. So, most books say that the […]
OSI Model
OSI Model OSI stands for Open System Interconnection. It is a referencing model that describes how information moves from one computer to another computer over the internet. The OSI model was developed by the ISO (International Organization for Standardization) in 1984. It is now become a popular architectural model. OSI consists of seven layers, and […]
Networking Models
Networking Models There are two main networking models that are available to communicate with different devices over the internet. Keep in mind OSI and TCP/IP are two different models built in almost the same period, and their functionality is almost similar. 1. OSI Model The OSI (Open System Interconnection) is a Theoretical (or Reference) Model that […]
Serial Vs. Non-Serial Schedules
Serial Vs. Non-Serial Schedules Serial schedules always hold the following properties Consistent Recoverable Cascadeless Strict But Non- Serial schedules do NOT always hold the following properties Consistent Recoverable Cascadeless Strict As in the serial schedule, the execution of the transaction is very slow because one transaction can be executed at a time. So, we did […]
Types of Recoverable Schedules
Types Of Recoverable Schedules The following diagram shows the types of recoverable schedules. Cascading Schedule Cascadeless Schedule Strict Schedule Cascading Schedule Casecadless Schedule Strict Schedule Cascading allows READ or WRITE operation for dependent Transaction (T2) before to T1 is committed or aborted. Casecadless Doesn’t allow READ to dependent Transaction (T2) until T1 is committed or […]
Recoverable Schedule In DBMS
Recoverable Schedule In DBMS Sometimes, a transaction may not execute completely due to some problems, i.e., hardware failure, software issue, system crash, etc. In that case, the failed transaction has to be rolled back to its starting point of time. If rollback is done successfully, then it will be a recoverable schedule in DBMS; otherwise, […]
Conflict Equivalent Schedule
Conflict Equivalent Schedule In the conflict equivalent, one schedule can be converted into another schedule by swapping just non-conflicting operations. Before learning conflict equivalent schedule, you must know about Conflict and non-conflict pairs. Swapping of pairs Remind Non-conflict pairs are always replaceable in the schedule Conflict pairs are never replaceable in the schedule Explain with […]
Topological Sort Examples
Topological Sort Examples Topological sorting is a fundamental concept in graph theory used to order tasks based on dependencies in a directed acyclic graph (DAG). It is widely used in scheduling, project planning, and dependency resolution in computer science. What is Topological Sort? Topological sort is a linear ordering of vertices in a directed graph […]
Serializability In DBMS
Serializability In DBMS Serializability is the highest level of isolation in DBMS. It ensures that, although transactions may be executed concurrently (in parallel), the end result is as if the transactions were executed in some serial order (one by one). This guarantees the consistency of the database even when transactions are running simultaneously. According to […]
Conflict in DBMS
Conflict in DBMS The conflict in DBMS happens when concurrent transactions try to access or modify the same data at the same time. It leads to inconsistencies or incorrect outcomes. Such conflicts generally occur in dbms when multiple transactions are executed concurrently. Types of Conflicts Various kinds of conflicts may occur in a DBMS, some […]
Schedule In DBMS
Schedule In DBMS When multiple transactions are running and their order of execution is needed then schedule in dbms comes into the picture. So that operations do not overlap with each other. In simple words, the schedule in DBMS defines the order of the execution for each transaction. Schedule types in DBMS There are two […]
Transaction States in DBMS
Transaction States in DBMS States through which a transaction goes during its lifetime are known as transaction states in DBMS. These states tell about the current state of the Transaction. Types Of Transaction States There are six major types of Transaction states, which are given below Active state Partially committed state Committed state Failed state […]
ACID Properties in DBMS
ACID Properties in DBMS ACID properties in DBMS ensure reliable and secure transaction processing by maintaining data integrity. They include Atomicity, Consistency, Isolation, and Durability, which together prevent errors and ensure correctness. A transaction is a set of operations that form a logical unit of work, where any failure results in the entire transaction being […]
Transaction In DBMS
Transaction In DBMS In Database Management Systems (DBMS), transaction management ensures that database operations grouped under a transaction are executed reliably, consistently, and securely. It guarantees that the database remains correct and free from anomalies, even in cases of system crashes, errors, or concurrent transactions. The key to transaction management is maintaining the ACID properties: […]
Equivalence of Two Sets of FD’s
Equivalence of Two Sets of FD’s In DBMS, For the equivalence of two sets of FDs, Two different sets of FDs for a given table may or may not be equivalent. If A and B are the two sets of FDs, then the following cases are possible Case 01: A covers B (A ⊇ B) Case-02: B covers […]
Decomposition Without Dependency Preserving
Decomposition Without Dependency Preserving If the decomposition of relation R with FDs (F), into R1 and R2 with their FDs (F1) and (F2), respectively, will be decomposition without dependency preservation if. Closure of F (F+) ≠ Closure of F1 (F1+) U Closure of F2 (F2+) In simple words, we can also say, After decomposition, IF […]
Dependency Preserving Decomposition
Dependency Preserving Decomposition As we know, table decomposition should be either lossless or dependency-preserving to avoid the loss of data. So, According to dependency preserving, The decomposition of relation R with FD’s (F) into relation R1 and R2 with their FDs (F1) and (F2) respectively, will be dependency preserving if. Closure of F (F+) = […]
Lossless Decomposition
Lossless Decomposition Lossless decomposition refers to the process of decomposing a relation (or table) into two or more smaller relations (tables) in such a way that no information is lost when the tables are joined back together. The lossless property ensures that the original data can be fully reconstructed by joining the decomposed relations, preserving […]